Now to growing concern in one neighborhood in california tonight where the ground underneath that neighborhood is slowly sinking. We've seen what sink holes have done before and recently which is why these neighbors are so worried. Here's abc's clayton sandell. Reporter: In this neighborhood in the northern california town of lake port, the hillside underneath is collapsing, taking with it trees streets and homes. The whole subdivision may have to move out. Reporter: Mike and janice were warned to empty the home they've lived in for 16 years and get out. We love it up here. We've always loved it up here. It's just devastating. All of this has happened within two months. We're just trying to stay optimistic. Reporter: The entire subdivision of 29 homes is in danger in this house dangling on the edge, the floor swallowed up. Look at the slope of the driveway, that home was sitting up above there. Reporter: Engineers are now desperately trying to find out why the hillside has become so unstable. So far there is no smoking gun. It's not the first time this land slide earlier this year on washington's state's whidbey island knocked homes after foundation. All anyone knows for sure is the ground is still moving, shifting entire lives along with it. What a horrible wait for them.

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